1. Field of the Invention
The present invention relates to a driving support device configured to receive externally transmitted information on vehicle traffic, which is transmitted from a communication device external to an own vehicle, and to give a notification of driving support information to a driver based on the externally transmitted information and own vehicle information.
2. Description of the Related Art
Hitherto, there has been known a driving support device configured to receive externally transmitted information, which is information transmitted from a roadside device, and to support driving of the driver based on the externally transmitted information and own vehicle information. For example, in a driving support device proposed in Japanese Patent Application Laid-open No. 2004-171459, traffic light information transmitted from a traffic light is received by an in-vehicle communication device as externally transmitted information. The traffic light information includes information on a lighting state and a lighting period of the traffic light. The driving support device is configured to calculate a period until the lighting state of the traffic light changes based on the traffic light information when the own vehicle is located near the traffic light, and to display this period on a display device. As a result, the driver can drive while recognizing the period until the lighting state of the traffic light changes.
A system configured to receive the externally transmitted information transmitted from the roadside device by the in-vehicle communication device, and to use the information for the driving support for the driver in this way is referred to as vehicle-infrastructure cooperative system. The externally transmitted information transmitted from the roadside device includes vehicle detection information on vehicles detected in a vicinity of an intersection and the traffic light information on lighting of a traffic light.
The driving support device is configured to operate a notification device so as to provide driving support information when a condition for providing a service for the driving support to the driver is satisfied based on the externally transmitted information and own vehicle information (information representing a position and a driving state of the own vehicle). For example, the driving support device estimates whether or not the driver is overlooking a red traffic signal based on the traffic light information and the own vehicle information. The driving support device is configured to sound a buzzer, and to display the words “Caution: Red Signal”, a mark, and the like on a screen of the display device as driving support information when such a condition that the driver is assumed to have overlooked a red traffic signal is satisfied. This can cause the driver to pay attention to the traffic light. The service of providing the driving support information to the driver is not limited to the red traffic signal overlook caution information, that is, a plurality of types of information are provided, and the driving support information is provided depending on an occasional state.
The driving support information is preferably displayed in a manner as visible to the driver as possible. In general, vehicle state information, which is to be notified to the driver, e.g., a vehicle speed, a fuel amount, a battery remaining amount, and a travel distance is displayed on a meter display provided in front of a driver's seat. Thus, the driving support information can also be displayed by using the meter display. In this case, however, the driver needs to change their line of sight during driving. Moreover, the displayed driving support information may be hidden by the steering wheel during a steering wheel operation, and visibility is thus not satisfactory. Therefore, the alert directed to the driver may be delayed.
On the other hand, a head-up display is known as a display high in visibility. The head-up display is configured to display an image on a front windshield on the driver's seat side. In this case, therefore, the driver does not need to change their line of sight and can easily recognize information. The head-up display is used as, e.g., a sub-display of a navigation system. However, for example, when the driving support information is displayed on the head-up display, the display space is limited, and thereby a strict restriction is thus imposed on information provision required by a system (e.g., the navigation system) that has been used.